If you want to recompile Keith's bootloader for different LED/Program pins then install the 60 day trial XC32 compiler, that's what I did.
Not sure if the free one will compile it small enough, not game to try it now that my setup works

The bootloader I recompiled for the DIP28 PIC32MX250F128B may have the 32KHz option enabled, these are for the RTC xtal on RB4,RA4, not populated on Fubar mini
I have not connected a 32Khz xtal to the pins to test the RTC feature, but I have tested RB4 and RA4 as I/O.

Bootloader needs to be recompiled as the Fubarino Mini uses RA8 as the program pin and RA10 as the LED, I use RA1 and RB15 on the DIP part.

I don't think it would require a new bootloader. You'd want to go into the bootloader project and created a new one (copy of the MX1 (serial) version that's there) set up just for your chip, but I think the only thing you'd be changing is the FLASH size (and maybe RAM size) and CPU part number. Should be a piece of cake.